On the evolution of an inner conflict.

A simple two-locus genetic model is suggested, in which a "conflict" between alleles located at different loci leads to the establishment under certain conditions of fixation of a double mutant type which is different from the wild type only in the fact that a smaller fraction of its offspring, either males or females, survive to maturity. The double mutant is characterized by conflicting features determined by the different loci. The results are obtained by an analysis of an exact genetic model, though they are partly interpreted in terms of locus-dependent kin selection.